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Core research project 1: Long-term variation mechanisms of greenhouse gas concentrations and their regional characteristics |
Research Plan > Core Research Projects > Results of 2008-2009 |
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[Results of fiscal year 2008-2009] |
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Large-scale atmospheric monitoring network |
In this project, we conduct monitoring of the atmosphere in the Asia-Pacific region, using aircrafts, marine vessels and ground based monitoring stations. By observing changes in atmospheric oxygen concentrations measured at Hateruma and Ochi-ishi stations, we can study CO2 balance. Based on these observations, the oceanic CO2 uptake is estimated to be 2Pg. Although there is a significant change in terrestrial CO2 uptake, it still seems to be a sink at present.
Recently, an increase in the concentration of another important greenhouse gas, methane, has been detected from ship observations. To clarify the influence of Asian emissions, we are expanding our observation sites to include sites in India, China and Southeast Asia. |
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Differences in seasonal variation of CO2 between Japan (Hateruma), China and India measured at the same latitude |
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Variation in CO2 concentration and its growth rate at Hateruma and Ochi-ishi |
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Averaged molar and mass composition of CFCs in the air masses from China and their percentages converted into GWP |
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Decrease in oxygen concentration and increase in CO2 measured at Hateruma monitoring station |
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Altitude-dependent differences in the seasonal variation of CO2 above international airports |
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Latitudinal CH4 concentration trends measured above the Pacific Ocean |
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Monitoring soil and plant respiration |
The amount of terrestrial CO2 uptake is greatly dependent on plant and soil organic carbon accumulation and annual variations in climatic conditions. We carry out research on ecosystem behaviors by analyzing forest flux data from the Fuji Hokuroku site. At the same time, we also conduct studies on geographical differences in the pattern of annual variations in CO2 flux at different sites in Japan, China and Korea as part of an Asian research network.
Furthermore, we have started field experiments such as heating the soil in an effort to artificially create climate change, and study changes in the rate of soil organic carbon decomposition under similar conditions to those occurring in nature. |
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Differences in respiration flux between 2006, 2007 and 2008 at Fuji Hokuroku site |
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Comparison of the gross photosynthesis production of Asian forests in 2003 |
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Relationship between soil respiration and temperature increase |
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Oceanic flux observation |
We conduct long-term monitoring of oceanic CO2 sinks in the North Pacific. The amount of CO2 uptake is generally increasing. However, we have found a relative increase in the western part and a relative decrease in the eastern part of the North Pacific. We are now investigating the causes of this trend. |
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Database and model research |
Using a newly developed simulation model, we have been able to increase the usability of detailed time sequence data. Using this coupled model, we carry out inverse calculation to analyze the emission areas and intensity of CO2 distribution. |
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Simulation of CO2 concentration in Hateruma
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Simulation of methane flux from China |
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We are also conducting analyses of global distribution of methane concentration, as well as oxygen, isotopes, 14C and CO. |
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